The thrust for year three will be the analysis of single cells (via Coulter sorter system) for such biologically important chemicals as chlorophyll and DNA. Attempts will be made to develop an assay for toxin in cells. This will be done on various stages of G. excavata from cultures (lag, log, late log, stationary, temporary cysts, "resting cyst-type") and cells and cysts isolated from nature. This will help to elucidate the suggested relationships between DNA, RNA, toxin level and cell cycle. In this way, entire populations can be analyzed resulting in statistically reliable information on single cell analysis of thousands of cells per run. The protocol has been worked out for all assays except the toxin assay. Stains to be used will be PI (propidium iodide), FDA (diacetyl fluorcein), acridine orange and other DNA stains. Populations will be sorted for further analysis and experimentation. It is hoped that this year's research will be the prelude for acquisition of a sorter superior to the TPS-1 that will be used for the initial year. The research on single cells can indeed become much more extensive with the more sophistocated systems.